1. Field of the Invention
The present invention relates to devices for maintaining a sharp cutting edge on a knife or other cutting tool, and particularly relates to devices for steeling or deburring the knife edge. The invention has particular application to deburring devices of the type wherein the knife edge is drawn along the intersection of two crossed deburring elements.
2. Description of the Prior Art
A number of knife edge sharpening or maintaining devices are known which utilize a pair of elongated crossed sharpening or deburring elements, wherein the knife edge is drawn through the notch formed by the intersection of the two crossed deburring elements, which elements respectively engage opposite sides of the knife edge. In some such devices a knife-receiving slot is provided for guiding the movement of the knife edge, the deburring elements being crossed so that their intersection overlies the slot. Typically the deburring elements are movably mounted so that, as the knife edge is drawn across their intersection, the pressure of the knife blade against the deburring elements simultaneously moves them so that their intersection point travels along the length of the deburring elements while remaining in alignment with the knife slot.
One such prior art deburring apparatus is disclosed in FIGS. 1 and 2, and is generally designated by the numeral 20. The deburring apparatus 20 includes a generally rectangular frame 21 having an elongated knife slot 22 formed in the upper end thereof. The frame includes of pair of downwardly converging upper edges 23 which lead into the upper end of the knife slot 22, each of the upper edges 23 being provided with a raised rib 23a running the length thereof centrally thereof. Projecting respectively from the side edges of the frame 21 at the upper ends thereof are two arms 24, each of which extends upwardly and then downwardly above a corresponding one of the upper edges 23, the inner ends of the arms 24 terminating a slight distance from each other so as to define a gap 25 therebetween. The arms 24 are respectively spaced above the upper edges 23 so as to cooperate therewith to define two inclined upper track slots 26 which converge downwardly and inwardly toward the center of the frame 21 and communicate with each other and with the knife slot 22. The arms 24 are respectively inclined with respect to the upper edges 23, so that the track slots 26 are wider at their inner ends than at their outer ends.
Also formed in the frame 21 at the lower end thereof are a pair of lower track slots 27 which converge upwardly and inwardly toward the lower end of the knife slot 22, but which are discrete therefrom and from each other. Each of the lower track slots 27 has an enlarged upper end 28. Extending the length of the lower edge of each of the lower track slots 27 centrally thereof is a raised rib 29.
A pair of deburring assemblies 30 are provided, each including an elongated cylindrical deburring rod 31 fixed at each end thereof to a. slider 32. Each slider 32 has a channel 33 formed in the lower face thereof defining a pair of depending legs 34. The rods 31 are crossed over the knife slot 22, with the sliders 32 being respectively disposed in the track slots 26 and 27. The channel legs 34 of each sliders 32 straddle the raised rib 23a or rib 29 of the corresponding track slot for guiding movement of the sliders 32 along the track slots. The ribs 23a are respectively parallel to the ribs 29 so that the deburring assemblies 30 undergo translational movement along the track slots 26 and 27.
In use, the sliders 32 are normally urged by gravity to the lower ends of the track slots 26 and 27 to the configuration illustrated in FIG. 1. As the knife blade is drawn between the deburring rods 30, the downward pressure on the rods 30 tends to move them apart, driving the intersection thereof downwardly along the knife slot 22, and forcing the rods 30 and the attached sliders 3 upwardly along the track slots 26 and 27.
The sliders 32 are arranged to facilitate assembly thereof with the frame 21. Thus, each of the sliders 32 will fit through the enlarged upper ends 28 of the lower track slots 27 for mounting on the raised ribs 29. Similarly, the lower ends of the upper track slots 26 are sufficiently wide to permit insertion of the upper sliders 32 therethrough to enable them to be mounted on the raised ribs 23a after the lower sliders 32 have been slid to the lower ends of the lower track slots 27.
However, this has caused difficulty in operation, since the upper sliders 32 tend to become disengaged from the ribs 23a and fall out of the upper track slots, particularly during cleaning with high pressure hoses. Furthermore, the upper sliders 32 sometimes tend to wedge in the narrowed upper ends of the upper track slots 26, preventing return of the deburring rods 30 to their normal rest position. Furthermore, it is possible for both of the upper sliders 32 to move up into a single one of the upper track slots 26 so that the intersection of the deburring rods 30 is moved out of alignment with the knife slot 22. Thus, when a knife edge is passed down through the gap 25, it may not pass between the two upper sliders 32 and into engagement with the deburring rods 30 at their intersection.